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7 ROBERT AERNOUT BARON VAN LYNDEN. AUXILIARY DEVICE FOR THE ETCHING 0F ARCH SHAPED WOLLASTON ,wmss FOR THE HEAT GONDUGTORS 0F THERMIC TELEPHONES.

APPLICATION FILED MMLZZ, 1919.

1 305 240 Patented May 27, 1919.

Wiltn ess lnvenZor UNITED STATES PATENT OFFICE.

ROBERT AEnNoUT BARON VAN LYNDEN, OF UTRECI-IT, NETHERLANDS, ASSIGNOR To NAAMLOOZE VENNOOTSCHAP DE NEDERLANDSCHE THERMO-TELEPHOON MAAT- scIIArrIJ, or UTREGHT, NETHERLANDS, A LIMITED LIABILITY COMPANY OF THE NETHERLANDS.

AUXILIARY DEVICE FOR-THE ETCHING OF ARCH-SHAPED WOLLASTQN WIRES FOR THE HEAT-CONDUCTOES OF THEIR/MIC TELEPHONES.

To all whom it may concern:

Be it known that I, ROBERT AERNOUT BARON VAN LYNDEN, a subject of the Queen of the Netherlands, residing at Utrecht, in the Province of Utrecht, in the Kingdom of the Netherlands, have invented certain new and useful Improvements in or Relating to Auxiliary Devices for the Etching of -Arch-Shaped Wollaston Wires for the Heat- Conductors of T hermic Telephones, of which the following is a specification.

This invention relates to an auxiliary device for the etching of arch shaped Wollaston wires for the heat conductors of thermic telephones.

During the etching of arch shaped Wollaston wires for the manufacture of heat conductors of thermic telephones the ex tremely thin arch shaped heat conductor is, while the piece of work is removed from the etching bath, subjected to deformations which may be occasioned by various causes. If the heat conductors are submerged together with their support the acid adhering to the bottom face of the aforesaid support during the removal from the etching bath may cause the thin heat conductor wire to bend and subsequently while being brought back in its hanging position to be damaged. In other cases the heat conductor wires merely by the surface tension of the etching bath or owing to grease or dust particles therein or other foreign matter adhering to the extremely thin wire sufi'er alterations both of their form and of their position. During the etching of the heat conductor members comprising a large number of loops arranged closely one near the other even slight oscillations of the etching bath may conjointly bring about a contact that will affect both the form and the position of the individual heat conductors.

The invention relates to an auxiliary device for the etching of arch shaped Wollaston wires whereby the above described dis advantage is as far as possible removed. The device consists of a supporting body of acid proof material detachably connected with the heat conductor carrier which body during the etching process and during the Specification of Letters Patent.

Patented May 27, 1919.

Application filed March 22, 1919. Serial No. 284,488.

removal of the heat conductors from the etching bath leans against the wire arch and thus forms a separate stay for the thin heat conductor wire being however adapted to be easily removed after the etching process and after the removal of the piece of work from the aforesaid stay.

On the accompanying drawing a form of execution of the present auxiliary device in conjunction with a simple heat conductor is represented in side view in Figure 1 whereas Fig. 2 shows a bottom view of the support ing body forming the auxiliary device.

With the illustrated device the arch shaped Wollaston wire a, whose bent portion or loop forms after the etching the actual heat conductor is with its legs a secured in the round heat conductor carrier a. Around the carrier 0 is placed a split elastic ring 01 which by way of example carries a hook shaped supporting piece e made of acid proof material for instance platinum, aluminium, glass or the like. The supporting iece e is arranged in such a manner that wit its free end it may come in contact with the wire arch a so as to support the aforesaid wire arch during the etching process and during the removal of the piece of work from the etching bath with sufiicient strength to guard against a possible bending or deformation.

In case a plurality of heat conductor arches are arranged on one carrier a separate supporting body is provided for each individual arch if the provision of one supporting body for several wire arches meets with difliculties. In many cases however a supporting body common to several arches may be arranged for instance in case the heat conductor arches are arrangedin an annular series on a common carrier.

At all events the arrangement must be such that the supporting body, the parts of the heat conductors being removed, may be easily withdrawn from the etching bath.

What I claim is: V

1. As an auxiliary support for Wollaston wires during the etching process, an acidproof guard adapted to engage such wires during and after the etching process and means whereby such guard may be connected detachably with a carrier of said wire.

2. As an auxiliary support for Wollaston wires during the etching process, a hooksliaped acid-proof guard adapted to engage the wire, and a split elastic attaching ring connected with said guard and extending transversely thereof, said ring being adapted for detachable connection with a carrier of 10 said wire.

In testimony whereof I have hereunto set my hand. 7

ROBERT AERNOU B BARON VAN LYNDEN. Witness:

H. V. HAGEN.

Gopies of this patent may be obtained for five cents each; by addressing the Commissionerof Patents,

Washington, D. G. 

